• Anurup Gohain Barua

      Articles written in Journal of Biosciences

    • The light of the firefly under the influence of ethyl acetate

      Anurup Gohain Barua Subhash Rajbongshi

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      When a firefly is made to inhale ethyl acetate vapour, a constant glow appears after a few minutes from its abdominal lantern. This control experiment has been performed by a few workers to record the emission spectrum of the firefly. However, a time-resolved experiment performed by us on this continuous light emitted by the species Luciola praeusta Kiesenwetter 1874 (Coleoptera : Lampyridae : Luciolinae) reveals that it is composed of a continuous train of tiny pulses! The nature of the pulses suggests that an oscillatory chemical reaction continues in the microsecond time scale in the lantern of the anaesthetized firefly.

    • Modulations in the light of the firefly

      Anurup Gohain Barua

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      Continuous light could be produced from the firefly by making it inhale vapours of ethyl acetate. Here we perform such a control experiment on the Indian species of the firefly Luciola praeusta Kiesenwetter 1874 (Coleoptera : Lampyridae : Luciolinae), and analyse the light in the microsecond time scale. The amplitude of the continuous train of triangular pulses is apparently altered in accordance with the instantaneous values of a hypothetical signal, which exhibits pulse amplitude modulation (PAM). In addition to sampling in amplitude, this scheme apparently provides sampling in time, representing pulse width modulation (PWM). A Fourier transform spectrum of this waveform shows the `carrier’ frequency and the accompanying `side bands’.

    • Bioluminescence emissions from the Indian winter species of firefly Diaphanes sp.


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      Numerous studies have been carried out on different aspects of the light from summer-active fireflies. Characteristicsof this light have led to very interesting conclusions on the chemiluminescence reaction as well as onthe nature of the light from live fireflies. Here we present a first report on bioluminescence emissions from anewly found winter-active Indian species of firefly Diaphanes sp. The steady-state emission spectrum from thisspecies comes out to be apparently similar to those from the other two Indian summer species, Luciolapraeusta and Asymmetricata circumdata: asymmetric in nature with a little bit of change in the position of thepeak wavelength and in the width of the full width at half maximum. An increase in temperature toapproximately 28 deg C causes a red-shift in the peak wavelength, which probably indicates denaturation of theenzyme luciferase in the live, flashing condition. Emissions in the time domain reveal that the light is nevercompletely off – it decreases in intensity to a low value, sometimes very close to zero, and then increases – acharacteristic unheard-of till date. Flash durations are considerably longer than those from the two Indiansummer species; those become shorter at about 28 deg C and increase to noticeably larger values at highertemperatures.

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